1. Field of the Invention
Example embodiments of the present invention relate to a substrate processing apparatus used for a manufacturing process of a semiconductor device, and more particularly, to a reflector for generating a neutral beam and a substrate processing apparatus including the same.
2. Description of the Related Art
Conventionally, in a manufacturing process of a semiconductor device, a plasma process may be used for a dry etching process, a physical or chemical vapor deposition process, a surface treatment process, etc. In a plasma process, a high frequency power may be applied to a chamber at the same time a reaction gas is supplied inside of the chamber. Accordingly, the reaction gas may be dissociated in the chamber to excite plasma by means of a glow discharge. At this time, ions included in the plasma may be used to perform substrate processing.
As semiconductor device become more integrated, integrated circuit design rules have decreased. For example, current integrated circuit design rules have decrease to approximately 0.1 μm or less. Accordingly, processing conditions of semiconductor processing apparatuses have become stricter in order to manufacture integrated circuits. Plasma processing apparatuses have been forced to improve to cope with the stricter manufacturing conditions. The improvement has been mainly obtained by techniques relating to increasing plasma density and/or uniformly distributing plasma.
However, no matter how the performance of a plasma is improved, the plasma has a specific limitation based on basic physical properties thereof. For example, because plasma includes a plurality of electrically charged ions and the ions collide with a semiconductor substrate and/or a specific material layer on a semiconductor substrate with an energy level of hundreds eV, the ions may cause physical and/or electrical damage to the semiconductor substrate and/or the specific material on the semiconductor substrate. For example, a surface of a single crystal semiconductor substrate and/or a specific material layer may be transformed into an amorphous state, and/or a chemical composition thereof may be changed. Further, an atomic bond in the surface layer may be broken due to an ion collision and a dangling bond may be generated. Still further, notching in a polysilicon layer due to charge-up damage on an insulating layer of a gate and/or a charging of a photo resist may be generated.
At least in part to solve some of the above described problems, research on a semiconductor element manufacturing process using a neutral beam instead of an ion beam has been performed. For example, substrate processing may be performed by neutralizing ions generated from a plasma and by directing the ions to a surface of a substrate. Conventional methods of neutralizing ions may include causing ions to collide with neutrons, electrons, and/or a reflection plate. A method of colliding ions with a reflection plate provides excellent efficiency of neutralization.
However, conventional methods that include generating neutral beams from ions colliding with a reflection plate have problems. For example, because ions may collide with a reflection plate with a high energy, the reflection plate may be thermally deformed. If a reflection plate becomes thermally deformed, an angle of a neutral beam reflected from the reflection plate may not be uniform, and thus a process yield may decrease and/or a procedure failure may occur.